deprecated: allow use of deprecated description methods

PR #633 removed these methods, but we can't do that without making a
breaking change release. Removing deprecated methods isn't worth doing a
breaking change release, so we instead simply allow them for now by
squashing the warnings.

Closes #633

Author: BurntSushi

CHANGELOG.md

@@ -1,3 +1,13 @@
+1.3.2 (2020-01-09)
+==================
+This is a small maintenance release with some house cleaning and bug fixes.
+
+Bug fixes:
+
+* [BUG #633](https://github.com/rust-lang/regex/pull/633):
+  Squash deprecation warnings for the `std::error::Error::description` method.
+
+
 1.3.1 (2019-09-04)
 ==================
 This is a maintenance release with no changes in order to try to work-around

regex-syntax/src/ast/mod.rs

@@ -176,6 +176,8 @@ pub enum ErrorKind {
 }
 
 impl error::Error for Error {
+    // TODO: Remove this method entirely on the next breaking semver release.
+    #[allow(deprecated)]
     fn description(&self) -> &str {
         use self::ErrorKind::*;
         match self.kind {

regex-syntax/src/error.rs

@@ -40,6 +40,8 @@ impl From<hir::Error> for Error {
 }
 
 impl error::Error for Error {
+    // TODO: Remove this method entirely on the next breaking semver release.
+    #[allow(deprecated)]
     fn description(&self) -> &str {
         match *self {
             Error::Parse(ref x) => x.description(),

regex-syntax/src/hir/mod.rs

@@ -91,6 +91,8 @@ pub enum ErrorKind {
 }
 
 impl ErrorKind {
+    // TODO: Remove this method entirely on the next breaking semver release.
+    #[allow(deprecated)]
     fn description(&self) -> &str {
         use self::ErrorKind::*;
         match *self {
@@ -113,6 +115,8 @@ impl ErrorKind {
 }
 
 impl error::Error for Error {
+    // TODO: Remove this method entirely on the next breaking semver release.
+    #[allow(deprecated)]
     fn description(&self) -> &str {
         self.kind.description()
     }
@@ -126,6 +130,8 @@ impl fmt::Display for Error {
 
 impl fmt::Display for ErrorKind {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // TODO: Remove this on the next breaking semver release.
+        #[allow(deprecated)]
         f.write_str(self.description())
     }
 }

src/error.rs

@@ -19,6 +19,8 @@ pub enum Error {
 }
 
 impl ::std::error::Error for Error {
+    // TODO: Remove this method entirely on the next breaking semver release.
+    #[allow(deprecated)]
     fn description(&self) -> &str {
         match *self {
             Error::Syntax(ref err) => err,